The present invention relates to a fuel injection pump for internal combustion engines.
More particularly, it relates to a fuel injection pump for internal combustion engines, which has a pump interior space constructed in a pump housing, a fuel delivery pump sucking fuel out of a fuel tank and delivering it into the pump interior space, a pressure control valve adjusting the fuel pressure in the pump interior space with a pump plunger executing at least an axial stroke movement, sucking the fuel out of the pump interior space during a suction stroke and apportioning the fuel injection pressure to at least one injection line during a delivery of a pressure stroke, a drive shaft rotating in a pump housing and driving the pump plunger to execute at least a stroke movement via a cam gear unit, and a hydraulic injection and adjusting mechanism for adjusting the start of the delivery stroke of the pump plunger with respect to the rotational position of the drive shaft and also with a control space and a spring space.
Such fuel injection pumps are known e.g. from GB 2 017 350 or DE 36 05 452 A1. Practical experience with these fuel injection pumps shows that unstable pressure vibrations frequently occur in the spring space of the hydraulic injection timing or adjusting mechanism used in such fuel injection pumps. These pressure vibrations trigger instability in the adjusting path of the injection adjusting piston, which results in defects in the operation of the fuel injection pump due to its displacing action on the cam gear unit.